cox & dhcp

Has anyone gotten linux and cox working using their dhcp server? I have
tried dhclient and dhcpcd and they both just time out. I thought maybe if
I used thier dhcp server name it might help. Do I need to use the
computer's cox hostname (cx-......) in the command line? These may sound
like assinine questions, but I'm trying to help a friend over the phone
who uses the service and he doesn't have a whole lot of information to
help me out with.